scholarly journals Titanite Ores of the Khibiny Apatite-Nepheline-Deposits: Selective Mining, Processing and Application for Titanosilicate Synthesis

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 446 ◽  
Author(s):  
Lidia Gerasimova ◽  
Anatoly Nikolaev ◽  
Marina Maslova ◽  
Ekaterina Shchukina ◽  
Gleb Samburov ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Cation Exchanger ◽  
Flow Diagram ◽  
Titanyl Sulfate ◽  
Process Flow Diagram ◽  
Flotation Cells ◽  
Selective Mining ◽  
Order Of Magnitude ◽  
Sulfuric Acid Method ◽  
Concentrated Sulfuric Acid

Geological setting and mineral composition of (apatite)-nepheline-titanite ore from the Khibiny massif enable selective mining of titanite ore, and its processing with sulfuric-acid method, without preliminary concentration in flotation cells. In this process flow diagram, titanite losses are reduced by an order of magnitude in comparison with a conventional flotation technology. Further, dissolution of titanite in concentrated sulfuric acid produces titanyl sulfate, which, in turn, is a precursor for titanosilicate synthesis. In particular, synthetic analogues of the ivanyukite group minerals, SIV, was synthesized with hydrothermal method from the composition based on titanyl-sulfate, and assayed as a selective cation-exchanger for Cs and Sr.

Analysis of Water-Soluble Polysaccharides in an Edible Medicinal Plant Epimedium: Method Development, Validation, and Application

2014 ◽  
Vol 97 (3) ◽  
pp. 784-790 ◽  
Author(s):  
Hua-Feng Zhang ◽  
Li-Li Niu ◽  
Xiao-Hua Yang ◽  
Lu Li
Keyword(s):  
Sulfuric Acid ◽  
Method Development ◽  
Colorimetric Method ◽  
Water Soluble ◽  
Optimal Conditions ◽  
Sulfuric Acid Method ◽  
Chinese Markets ◽  
Concentrated Sulfuric Acid ◽  
Phenol Sulfuric Acid ◽  
Interday Precision

Abstract Water-soluble polysaccharides are important constituents with evident health benefits in Epimedium. The aim of this study was to establish a specific, accurate, reproducible, and sensitive phenol-sulfuric acid method for the quantitative assay of Epimedium polysaccharides and to determine polysaccharides in Epimedium samples from Chinese markets. Galactose was adopted as the standard monosaccharide, and 486 nm was chosen as the detection wavelength. The optimal conditions for the color reaction were obtained using single factor experiments and an orthogonal test: temperature, 20°C; amount of 5% phenol, 0.3 mL; amount of concentrated sulfuric acid, 3.5 mL; incubation time, 20 min; and addition sequence, phenol-sample-sulfuric acid. The colored sample solution after chromogenic reaction exhibited high stability within 2 h. The calibration curve was linear within the range 5.00–60.00 μg/mL, and the correlation coefficient of the regression equation was 0.999. LOD and LOQ were 1.65 and 5.00 μg/mL, respectively. Recovery, intraday precision, interday precision, and accuracy were 97.43 to 103.80%, 0.73 to 3.48%, 1.21 to 2.75%, and 97.74 to 101.62%, respectively. Polysaccharides in 26 samples of Epimedium collected from different provinces of China were quantified by the proposed colorimetric method, and a large variation of contents of polysaccharides was observed among these samples.

scholarly journals Efficiency of Sulfuric Acid on Selective Scandium Leachability from Bauxite Residue

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 915 ◽  
Author(s):  
Maria Ochsenkuehn-Petropoulou ◽  
Lamprini-Areti Tsakanika ◽  
Theopisti Lymperopoulou ◽  
Klaus-Michael Ochsenkuehn ◽  
Konstantinos Hatzilyberis ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Ph Value ◽  
Bauxite Residue ◽  
Scale Up ◽  
Advanced Technology ◽  
Flow Diagram ◽  
Ambient Conditions ◽  
Critical Metals ◽  
Process Flow Diagram ◽  
Leaching Condition

Bauxite residue (BR) is a well promising resource for critical metals, especially scandium (Sc), a rare and expensive metal with increasing applications in advanced technology. Greek BR seems to significantly favor a commercially viable recovery of Sc combining optimized leaching and advanced separation techniques. Leaching with mineral acids emerges as the dominant selection compared to other techniques. This study investigates an optimized leaching condition set for Sc recovery, using the most advantageous option of sulfuric acid. The main target is to develop a leaching scale-up process to be established in the premises of Mytilineos S.A. (formerly Aluminium of Greece, the largest Greek alumina and aluminum producer), taking into account the feed requirements of a subsequent advanced ion exchanged procedure. Several parameters were studied individually or combined in order to achieve high Sc concentration in the leachate and to ensure selectivity, especially concerning iron. The most significant parameters prove to be the solid-to-liquid ratio (S/L), the final pH value, and the leachate’s recycling. The proposed process, with low molarities of sulfuric acid and ambient conditions, integrates rapidly, leading to high and selective Sc recovery. Finally, a leaching process flow diagram under continuous operation on an industrial scale is developed.

scholarly journals Determination of tea polysaccharides in Camellia sinensis by a modified phenol-sulfuric acid method

2010 ◽  
Vol 62 (3) ◽  
pp. 669-676 ◽  
Author(s):  
Xionggang Xi ◽  
Xinlin Wei ◽  
Yuanfeng Wang ◽  
Qinjie Chu ◽  
Jianbo Xiao
Keyword(s):  
Sulfuric Acid ◽  
Camellia Sinensis ◽  
Incubation Temperature ◽  
Experimental Conditions ◽  
Acid Method ◽  
Relative Standard ◽  
Sulfuric Acid Method ◽  
Concentrated Sulfuric Acid ◽  
Phenol Sulfuric Acid

A direct procedure for the determination of total polysaccharides (TPS) in Camellia sinensis was set up based on the modified phenol-sulfuric acid method. The monosaccharide composition of TPS was analyzed by GC. Based on the results of GC, model monosaccharide mixtures were made which provided an adequate standard for this procedure. Through single-factor and orthogonal (L934) experiments, the experimental conditions such as the volume of phenol, the volume of concentrated sulfuric acid, the reaction time, and the incubation temperature, were optimized. The highest sensitivity of absorbance was obtained when the volume of concentrated sulfuric acid, the volume of phenol (6%), and the incubation temperature were 2.5 ml, 0.2 ml, and 50?C, respectively. Under optimum conditions, the prepared samples were determined satisfactorily, with the recovery from 100.2% to 103.7%, and a relative standard deviation (RSD) of 2.1%. Overall, the modified method is easily operated, rapid, sensitive and accurate. A similar procedure can be applied to the determination of other plant polysaccharides as well. .

Gallium Arsenide Integrated Circuits Decapsulation Technique Using Mixed Acid Chemistry For Die-Level Failure Analysis

2018 ◽  
Author(s):  
Harold Jeffrey M. Consigo ◽  
Ricardo S. Calanog ◽  
Melissa O. Caseria
Keyword(s):  
Gallium Arsenide ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
Mixed Acid ◽  
Optimum Parameters ◽  
Plastic Package ◽  
Fuming Nitric Acid ◽  
Concentrated Sulfuric Acid

Abstract Gallium Arsenide (GaAs) integrated circuits have become popular these days with superior speed/power products that permit the development of systems that otherwise would have made it impossible or impractical to construct using silicon semiconductors. However, failure analysis remains to be very challenging as GaAs material is easily dissolved when it is reacted with fuming nitric acid used during standard decapsulation process. By utilizing enhanced chemical decapsulation technique with mixture of fuming nitric acid and concentrated sulfuric acid at a low temperature backed with statistical analysis, successful plastic package decapsulation happens to be reproducible mainly for die level failure analysis purposes. The paper aims to develop a chemical decapsulation process with optimum parameters needed to successfully decapsulate plastic molded GaAs integrated circuits for die level failure analysis.

PRODUCTION OF SULFOCATIONITE BY MODIFICATION OF NATURAL COAL WITH CONCENTRATED SULFURIC ACID

2020 ◽  
Vol 3 (441) ◽  
pp. 104-109
Author(s):  
N.A. Bektenov ◽  
◽  
N.C. Murzakassymova ◽  
M.A. Gavrilenko ◽  
А.N. Nurlybayeva ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Concentrated Sulfuric Acid ◽  
Natural Coal

Addition of primary alcohols to 3-chlorononafluoro-1,5-hexadiene and perfluoro-1,3,5-hexatriene

1985 ◽  
Vol 50 (8) ◽  
pp. 1714-1726 ◽  
Author(s):  
Václav Dědek ◽  
Igor Linhart ◽  
Milan Kováč
Keyword(s):  
Sulfuric Acid ◽  
Primary Alcohols ◽  
Principal Product ◽  
Allyl Rearrangement ◽  
Concentrated Sulfuric Acid ◽  
Sodium Alkoxide

Sodium alkoxide-catalyzed addition of methanol, ethanol and propanol to 3-chlorononafluoro-1,5-hexadiene (I) proceeds at temperatures -35 °C to 8 °C with allyl rearrangement, affording 1,6-dialkoxy-1,1,2,3,4,4,5,6,6-octafluoro-2,4-hexadiene (V) as the principal product, along with 1,6-dialkoxy-1,2,3,3,4,5,6,6-octafluoro-1,5-diene (VI) and trans-1,6-dialkoxy-1,1,2,3,4,4,5,6,6-nonafluoro-2-hexene (VII). The ethers Va-Vc consist of the cis,trans- and trans,trans-isomers in about 3 : 1 ratio, whereas the ethers VIa-VIc have trans,trans-configuration. Ethers Vc and VIc react with concentrated sulfuric acid to give dipropyl 2,3,4,5-tetrafluoro-2,4-hexadienedioate (IX) and dipropyl 2,3,4,4,5-pentafluoro-2-hexenedioate (X), respectively, whereas the ether VIIc affords a mixture of propyl 6-propyloxy-2,3,4,4,5,6-heptafluoro-2-hexenoate (XI) and ester X. Addition of methanol to perfluoro-1,3,5-hexatriene (II) affords 1,1,2,3,4,5,6,6-octafluoro-1,6-dimethoxy-3-hexene (XIII) as the principal product.

scholarly journals 4,5,6-Trichloropyrimidine-2-carboxamide

Molbank ◽  
10.3390/m1190 ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. M1190
Author(s):  
Andreas S. Kalogirou ◽  
Panayiotis A. Koutentis
Keyword(s):  
Sulfuric Acid ◽  
Elemental Analysis ◽  
Maldi Tof ◽  
Concentrated Sulfuric Acid

Reaction of 4,5,6-trichloropyrimidine-2-carbonitrile (1) with concentrated sulfuric acid at ca. 20 °C gave 4,5,6-trichloropyrimidine-2-carboxamide (5) in 91% yield. The new compound was fully characterized by IR, MALDI-TOF, NMR and elemental analysis.

scholarly journals Backstepping Methodology to Troubleshoot Plant-Wide Batch Processes in Data-Rich Industrial Environments

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1074
Author(s):  
Federico Zuecco ◽  
Matteo Cicciotti ◽  
Pierantonio Facco ◽  
Fabrizio Bezzo ◽  
Massimiliano Barolo
Keyword(s):  
Production Capacity ◽  
Batch Process ◽  
Batch Processes ◽  
Flow Diagram ◽  
Production Cycle ◽  
Multivariate Statistical ◽  
Process Flow Diagram ◽  
Root Cause ◽  
Industrial Batch ◽  
Specialty Chemical

Troubleshooting batch processes at a plant-wide level requires first finding the unit causing the fault, and then understanding why the fault occurs in that unit. Whereas in the literature case studies discussing the latter issue abound, little attention has been given so far to the former, which is complex for several reasons: the processing units are often operated in a non-sequential way, with unusual series-parallel arrangements; holding vessels may be required to compensate for lack of production capacity, and reacting phenomena can occur in these vessels; and the evidence of batch abnormality may be available only from the end unit and at the end of the production cycle. We propose a structured methodology to assist the troubleshooting of plant-wide batch processes in data-rich environments where multivariate statistical techniques can be exploited. Namely, we first analyze the last unit wherein the fault manifests itself, and we then step back across the units through the process flow diagram (according to the manufacturing recipe) until the fault cannot be detected by the available field sensors any more. That enables us to isolate the unit wherefrom the fault originates. Interrogation of multivariate statistical models for that unit coupled to engineering judgement allow identifying the most likely root cause of the fault. We apply the proposed methodology to troubleshoot a complex industrial batch process that manufactures a specialty chemical, where productivity was originally limited by unexplained variability of the final product quality. Correction of the fault allowed for a significant increase in productivity.

Sign in / Sign up

Export Citation Format

Share Document